Siloxane copolymers of allyl ethers



United States Patent 3,176,034 SILOXANE COPOLYMERS F ALLYL ETHERS HaroldA. Clark, Midland, Mich, assignor to Dow Corning Corporation, Midland,Mich, a corporation of Michigan No Drawing. Filed Nov. 13, 1961, Ser.No. 152,031 8 Claims. (Cl. 260-44822) This invention relates tothermally stable copolymers of polynuclear aromatic ethers andsiloxanes. This application is a continuation-in-part of the US.application Serial No. 121,830, filed July 5, 1961, now abandoned.

One of the persistent problems in the silicone field has been therelatively poor adhesion between silicone resins and metals. Thisproblem has been particularly bothersome in the productionof printedcircuits wherein ice with siloxanes of the formula R1 R2 R3 nsnosomosinin the presence of a platinum catalyst. Suitable catalysts includeplatinum-on-charcoal, platinum-on-alumina or compounds of platinum suchas chloroplatinic acid. The reaction proceeds smoothly at temperaturesfrom 50 C. to 150 0., although these temperatures are not critical. Thereaction proceeds by the addition of the SiH compound to the double bondof the allyl group on the ether to produce linear polymeric material.

The degree of polymerization of the polymer above described, varies withthe mol ratio of the respective units. Thus, when one reacts 2 mols ofthe above allyl ethers with one mol of the above defined siloxanes, oneobtains a trimeric polymer of the formula a copper circuit is applied toa silicone resin base. No satisfactory adhesive has been known forsecuring the copper to the silicone resin. However, because siliconeresin based printed circuits are to be operated at elevated temperature,it is necessary that the adhesive have the best possible thermalstability.

It is the object of this invention to provide novel compositions ofmatter which are useful as adhesives between silicone resins and metals.Another object is to provide polymeric compositions, useful as coatingsand as electrical insulation. Other objects and advantages will beapparent from the following description.

The invention relates to copolyrners consisting essentially of (1) unitsof the formula selected from the group -ornonxomoOmOo onzonxornandon,=oxorno,.o chromatin,-

and (2) units of the group which units are interconnected through SiCbonds, in which copolymer the mol ratio of total units (1) to totalunits (2) is from 1:2 to 2:1, in said units each X is of the grouphydrogen, methyl and halogen, each Y is of the group C(CH CH C(CH (C 11HC(CH and O, a has a value from 0 to 1, R is of the group phenyl andmethyl radicals, there being at least one phenyl group per two methylgroups and m has a value from 0 to 50 inclusive. I

The compositions of this invention are fluid thermoplastic materials,which are best prepared by reacting allyl ethers of the formula When onereacts 2 mols of the above siloxanes with 1 mol of the above allylethers, the resulting product is a trimeric compound, both ends of whichconsist of SiH groups. When the mol ratios of the siloxane and the allylethers fall between these two limits, higher polymers are obtained. Thehighest polymers are obtained when one mol of the siloxane is reactedwith one mol of the allyl ether. In this case, one end of the polymerwill be the group CH =CXCH O.- and the other end of the polymer will beof the group The thermoplastic products of this invention can beconverted into cured thermoset resinous materials by reacting them withpolyfunctional siloxanes containing either silicon-bonded vinyl groupsor silicon-bonded hydrogen atoms (SiH groups) or combinations of both.The precise polyfunctional siloxane chosen for cross-linking thepolymers will depend on the type of end group ing present in the basepolymer. Where the end groups in the base polymers are allyl groups, thecross-linker should contain SiH groups. Where the end groups in the basepolymer are SiH groups, the cross-linker should contain silicon-bondedvinyl groups. The reaction between the base polymer and the cross-linkeris brought about by a platinum catalyst under the same conditions asabove described.

It should be understood that the cross-linker can contain both SiH andvinyl groups when the base polymer contains both SiH and allylendblocking groups.

For best performance, it is preferable that the crosslinker becompatible with the base resin. It is preferable that the cross-linkerbe a phenyl-containing siloxane.

The allyl ethers employed in this invention are known materials, some ofwhich are described in US. Patent No. 2,227,805. The best method forpreparing the ethers employed in this invention is shown in said patentand consists of reacting the alkali metal salts of the correspondingdiphenyl diols of the formula be, for 'example,sucl1 siloxanes astetraphenyldisiloxane;

syrri-diplienyldimethyldisiloxane; 1, '1 diphenyl 3,3-dimethyl-'di's'iloxane; 1,5-diphenyl, 1, 3, 3,S-tetramethyltrisiloxa'ne;'1,1, 5, 5-tetramethyl-3,3-diphenltrisiloxane;

I alt I a a 3): H31 0 S 5111 (CHM e a): (CH3):

and HSi O[Si0]u sin In the commercial utilization of the composition ofthis invention for the preparation of thernrosetting adhesives, oneshould first react the allyl ethers with the difunctional s-iloxanes toproduce the base polymer. One can then mix the appropriate cross-linkingsiloxane and the platinum catalyst and heat to cure the mixture to atough, pliable, cross-linked material. If long shelf life is desired,-it is best not to mix the platinum catalyst and/or the cross-linker withthe base resin until within a few 4 The above fluid polymer was mixedwith 1.36 parts by weight of the compound C H Si[OSi(CH CH=CH Themixture was warmed at to 50 C. to allow bubbles to escape and thenheated at 150 C. overnight. A tough, thermoset, flexible resin whichshowed excellent adhesion to aluminum and copper was obtained.

EXAMPLE 2 3.9 parts by Weight of sym-diphenyldimethyldisiloxane wasmixed with 3.33 parts by weight of I and 5 parts by weight toluene. Atrace of the platinum catalyst of Example l was added and the mixturewas heated on a hot plate to give a viscous fluid polymer havingthe'aver'age molecular configuration C0H5 013115 G5H5 0 5115 HSlOSiCDCDCDODCSi OSIIH CH3 H3 H3 CH3 where C and D are as defined inExample '1. V The above base resin was mixed with 14.13 parts by weightof the cross-linker of Example 1 and cured in accordance with the methodof this example. The resulting product was a tough, flexible resinousadhesive.

EXAMPLE 3 2.6 parts by weight of sym-diphenyldimethyldisiloxane, 3.99parts by weight of I and 5 parts by weight toluene were mixed with atrace of the platinum catalyst of Example 1. The mixture was warmed toreflux the solvent and there was obtained a polymeric material havingthe average formula hours of use. This is true because curing occursgradually at room temperature. However, it is possible to prolong theshelf life of the completely formulated material by keeping it attemperatures of -20 C. or below.

The following examples are illustrative only and should not be construedas limiting the invention which is properly delineated in the appendedclaims.

EXAMPLE 1 39 parts by weight of sym-diphenyldimethyldi-siloxane wasmixed with 2.66 parts by weight of 4, 4'-bis-allyloxybiphenyl(hereinafter referred to as I) and the mixture 'was diluted with 5 partsby weight toluene. A trace of a .37 percent by weight platinum in theform of a solution of 'chloroplatinic acid in buta'nol was mixed withthese ingredients. The mixture was then warmed on a hot plate. A fluidpolymer resulted. letting C represent the unit '-on,on,omo001120112011,-

and D'represent the polymer unit cm, can.

-si OSi this polymer had the average formula 05H5 CsHn o ts 0 5 11511OSlCDCSlO SIH CH JH Ha 3 1.1 part of the cross-linker, C H Si[OSi(CH H]was added to this material. The mixture was dissolved in toluene and thesolvent was evaporated and'the residue Was heated at C. to give aflexible, resinous material.

EXAMPLE 4 Employing the procedure of Example 1, 5 parts by Weight of[(CH HSiO] Si(C H 3.3 parts by weight of I and 5 parts by Weight toluenewere mxed with the catalyst of Example 1 and reacted to give a fluidpolymer of the average formula HSl 0S1 OSlCFCFCFCFGSi 0S1 OSIH In theformula, F represents the group 3M 0 5): M S1 O Si O Siand C is as abovedefined.

The fluid polymer was mixed with .68 part by weight of the cross-linkerof Example 1 and heated at 150 C. to give a'tough, fiexible'cured resin.

EXAMPLE 5 When the following allyl ethers are reacted with the following'siloxanes in amount of 2 mols of the ether to one mol of the siloxanein accordance with the procedure of Example 1, the following productsare obtained. When each of these products is reacted with an equivalentamount of CH Si[OSi(C H (CH )H] 3 in the presence of Pt dispersed onalumina at a temperature of 150 C. a tough, resilient resinous materialis obtained.

That which is claimed is:

1. A composition of matter consisting essentially of polynucleararomatic ether-siloxane polymeric fluids selected from the groupconsisting of 8 5. A fluid copolymer of (a) at least one unit of theformula omonxomoGmOo oH,oX=cH,;

| 2 nmsnosumosicmonxomoOmOo CH CHX- CHgSIIIOSPmOSiRzH; and

R1 R2 (3) copolymers having (a) at least one-CH CHXCH OOYQOO CH CHXCH-unit,

(b) at least one-sflOsilmOsi-unit and (a) terminal units selected fromunlts of the group consisting ol' HRzSi[SlR-3]m0S1- andOHFOXCLBOOLOOomonxomwherein the ratio of (a) units to (b) units isbetween 1/2 and 2/ 1, each X being selected from the group consisting ofhydrogen, methyl and halogen, each Y being a divalent group selectedfrom the group consisting of a has a value from 0-1 inclusive, each R isselected from the group consisting of phenyl and methyl radicals, therebeing at least one phenyl radical per two methyl radicals and m has avalue from 0 to 50 inclusive.

2. A composition of matter as defined in claim 1 further characterizedin that a is 0, X is hydrogen and the ratio of methyl to phenylsubstituents is 1/1.

3. A fluid polymer of the general formula Ra R2 R:

where each X is selected from the group consisting of hydrogen andmethyl and halogen, each Y is a divalent radical selected from the groupconsisting of 1 2. 1mm) (CIHE), I H Q, I X M and -0- a has a value from0 1 inclusive, each R is selected from the group consisting of phenyland methyl radicals, there being at least one phenyl radical per twomethyl radicals and m has a value from 0 to 50 inclusive.

4. A fluid polymer of the general formula (b)" at least one unit of theformula "''Si[OSi]mOSi and (c) terminal units selected fromthegroupconsisting of units of the formulae and the ratio of (a) unitsto (b) units being greater than 1/2 and less than 2/ 1, each X being amonovalent substituent selected from the group consisting of'hydrogen,methyl, and halogen, each Y being a divalent group selected from thegroup consisting 'of 1 X I HRzSiIOSflmOgiCHgCHXCH OY O CHBOHXCHHSHOSHOSiRIH where each R is a monovalent substituent selected from the groupconsisting of methyl and phenyl radicals, there being at least onephenyl radical per two methyl radicals, each X is a monovalentsubstituent selected from the group consisting of hydrogen, methyl, andhalogen, each Y being a divalent group selected from the groupconsisting of I F I, I W a) 2 5), I W a), {X 92 and -0- a has a valuefrom 0-1 inclusive and m has a value from 0-50 inclusive.

References Cited by the Examiner UNITED STATES PATENTS 2,637,738 5/53Wagner 260-465 2,915,497 12/59 Clark 260-465 "FOREIGN PATENTS 599,8916/60 Canada.

803,129 10/58 Great Britain.

MURRAY TILLMAN, Primary Examiner.

' J LIBERMA'N; WILLIAM H. "SHORT,"Examiners.

UNITED STATES PATENT CFFICE CERTIFICATE OF CORRECTION tent No. 5,176,034March 30, 1965 Harold A. Clark It is hereby certified that error appearsin the above numbered patrequiring correction and that the said LettersPatent should read as rected below.

Column 2, lines 2 to 4, the formula should appear as shown low insteadof as in the patent: l V

. 2 2 z .Hsimsn osia me column 2 lines 18 to 20, the formula shouldappear as 1own below instead of as in the patent: i

3H =CXCH 0 Y I OCH CHXCH 51(051) SiCH CHXCH 0 Y OCH2CX=CH 2 2 a 2 2 m 22 a 2 )lumn 3, lines 72 to 75, theformula should appear as. shown alowinstead of as in the patent:

(i H C6HTS C6H5(':6H5 I HSi OSi--CDCSiO ifH- CH3 CH3 H3 H olumns 5 and6, in the Table",- under the column heading "Allyl ther", formula (3)should appear as shown below instead of as I n the patent:

CH2=CHCH2OO-C-OOCH2CH=CH2 same columns 5 and 6, same table, under thesame heading, formula [4) should appear as" shown "below-instead of asin the patent:

(H3 H3 CH =CCH OO-C-OOCH CCl=CH same columns 5 and 6, same table, underthe heading "Product" for that-portion of the first formula reading mi s2 CIHS s z s SiCH CHCH O read SiCH cacn o same columns. v5 and .6, samevtable, under the same heading, formula (6) for that portion of theformula reading column 7, lines 28 and 29, for that portion of theformula reading CH =CXCH OOY OOCH CHXCH =CXCH OOY QO'CH CHXCH Signed andsealed this 22nd day of February 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. A COMPOSITION OF MATTER CONSISTING ESSENTIALLY OF POLYNUCLEARAROMATIC ETHER-SILOXANE POLYMERIC FLUIDS SELECTED FROM THE GROUPCONSISTING OF